Changes in the Acetylcholinesterase Enzymatic Activity in Tumor Development and Progression

Anti-carcinogenic effects of arecaidine but-2-ynyl ester tosylate on breast cancer: proliferation inhibition and activation of apoptosis

BACKGROUND

Breast cancer (BC) is the most prevalent cancer among women globally and is notoriously difficult to treat due to its heterogeneous nature and the lack of an effective treatment. Muscarinic receptors (MRs), which serve as key regulators in the parasympathetic nervous system, exhibit significant regulatory functions in non-neural cells. Recent studies suggest that modulating MR activity can elicit anti-carcinogenic effects across various malignancies, stimulating interest in their oncological implications. To investigate this further, we explored the anti-carcinogenic effects of arecaidine but-2-ynyl ester tosylate (ABET), a potential M2 receptor activator, in BC cells using several cellular and molecular assays.

METHODS AND RESULTS

Molecular docking assays were employed to confirm the binding affinity of ABET to M2/M4 receptors. Subsequently, we evaluated the impact of ABET on cell viability, proliferation, clonogenicity, and migration in MDA-MB-231 and MCF-7 BC cell lines. Computational analysis revealed preferential binding of ABET to M2 and M4 receptors. In-vitro experiments demonstrated that ABET markedly inhibits viability, growth, clonogenicity, and migration in BC cells. Notably, ABET induced cell cycle arrest in MDA-MB-231 cells and promoted apoptotic cell death in MCF-7 cells. Furthermore, ABET downregulated key proliferation- and cell cycle-associated genes, including CCND1, CDK6, and MKI67.

CONCLUSIONS

Our findings underscore ABET as a promising therapeutic candidate for BC treatment, capable of suppressing cell growth, survival, and migration. Additional in-vivo studies are necessary to validate ABET's anti-neoplastic efficacy and evaluate its feasibility as novel therapeutic agent in BC management.

Design of reversible cholinesterase inhibitors: Fine-tuning of enzymatic activity by PAMAM-calix-dendrimers

Reversible cholinesterase (ChE) inhibitors are widely used drugs for the therapy of various cognitive and neurodegenerative disorders. The development of a "universal drug" with easily tunable ChE inhibition activity is a relevant interdisciplinary problem. Here we propose for the first time the design of novel "fine-tuned" ChE inhibitors based on dendrimers with a thiacalix[4]arene core (PAMAM-calix-dendrimers). A series of first-generation PAMAM-calix-dendrimers with different terminal fragments were designed and synthesized. The human acetylcholinesterase and butyrylcholinesterase inhibition by PAMAM-calix-dendrimers was confirmed by molecular docking and in vitro studies. PAMAM-calix-dendrimers were found to have IC50 values for acetylcholinesterase and butyrylcholinesterase in the range of 0.076-5400 μM. Relationships between the structure of PAMAM-calix-dendrimers and the ChE inhibitory activity were established. The conformation of the macrocyclic core and the nature of the terminal groups were found to exert a direct impact on the inhibitory activity of dendrimers. We anticipate our study to be a starting point for creation of "universal drug" with tunable ChE inhibitory activity to specific therapeutic targets, and more sophisticated in vivo studies of such systems.

Diethyl nitrosamine-induces neurobehavioral deficit, oxido-nitrosative stress in rats' brain: a neuroprotective role of diphenyl diselenide

Diethylnitrosamine (DEN), a common dietary carcinogen, is associated with neurotoxicity in humans and animals. This study investigated the neuroprotective effects of diphenyl diselenide (DPDS) against DEN-induced neurotoxicity in male Albino Wistar rats (n = 40). Rats were randomly distributed into cohorts and treated as follows: vehicle control (corn oil 2 mL/kg; gavage), DPDS-only (5 mg/kg; gavage) and DEN-only (200 mg/kg; single dose i.p.). Also, two other rat cohorts were pre-treated with DPDS (3 or 5 mg/kg) for 15 days (day: 0-15), subsequently administered with DEN (200 mg/kg) and continuously treated with DPDS for another 7 days, (days:15-21). Behavioural tests (OFT- using the open field test; NORT- novel object recognition test; FST- forced swimming test and Y-maze) were conducted from days 19-21, followed by biochemical analysis of the hippocampus and prefrontal cortex for oxidative stress, inflammation, neurotransmitter metabolic enzyme, and histopathology. DEN-treated rats exhibited decreased locomotor activity, spatial memory function and antioxidant activity, increased oxidative and nitration stress, anxiety, and depressive-like behaviour, causing histoarchitectural damage in prefrontal and hippocampal cortices. DPDS treatment (pre- and post-DEN exposure) significantly alleviated these neurotoxic, oxidative, and nitration effects, reversed DEN-induced histopathological alterations, and improved locomotive and cognitive functions. In conclusion, DPDS demonstrates potent neuroprotective effects against DEN-induced toxicity, likely through enhanced endogenous antioxidant capacity that mitigates oxido-nitrative damage. These findings suggest that the organo-selenium -DPDS- is a promising chemotherapeutic agent potent in alleviating DEN-mediated neurotoxicity and maintaining brain health.

Preparation and characterization of AChE immobilized magnetic bio-nanocomposites (Fe3O4@Cht/Au) for pesticide detection

Free enzymes cause difficulties in many applications due to their insufficient stability, loss of activity in a short time, and most importantly, although they are costly, they are used only once in reactions, lose their effect and cannot be recovered from the environment. Magnetic nanoparticles coated with biocompatible polymeric material are potential candidates for promising enzyme carriers due to their multifunctional pore surfaces, easy removal from the environment provided by the magnetization, ability to main stability under various harsh conditions. This study prepared a biosensor candidate based on the inhibiting acetylcholinesterase enzyme by organophosphate pesticides from chitosan-coated magnetic nanoparticles doped with gold. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction diffractometry, and Fourier transform infrared spectroscopy analysis confirmed the structure of synthesized nanocomposites. Magnetic characteristics of the nanocomposites were assessed using VSM. Bio-nanocomposite (Fe3O4@Cht/Au/AChE) was used to determine environmental pollutants qualitatively. Remediation of organophosphate-containing wastewater is an essential issue for environmental sustainability. In this work, Dichlorvos and Chlorpyrifos were selected as organic pollutants to assess the enzymatic activity of immobilized Fe3O4@Cht/Au/AChE. Optimum conditions for AChE enzyme were immobilized nanostructures (Fe3O4@Cht/Au/AChE) were determined. The optimum pH for the immobilized enzyme was found to be 8, and the optimum temperature was found to be 60 °C. Retained immobilized enzyme activity is found to be around 50% for the 20th reuse. In the presence of 150 µL pesticide, retained immobilized enzyme activity is found to be around 25%. Method validation was performed for pesticides. When using immobilized AChE, the LOD (limit of detection)-LOQ (limit of quantitation) values for Dichlorovos and Chlorpyrifos was obtained in the range of 0.0087-0.029 nM and 0.0014-0.0046 nM, respectively. The relative standard deviation (RSD%) values, which are indicators of precision, were found to be below 2%.

Britanin - a beacon of hope against gastrointestinal tumors?

Britanin is a bioactive sesquiterpene lactone known for its potent anti-inflammatory and anti-oxidant properties. It also exhibits significant anti-tumor activity, suppressing tumor growth in vitro and in vivo. The current body of research on Britanin includes thirty papers predominantly related to neoplasms, the majority of which are gastrointestinal tumors that have not been summarized before. To drive academic debate, the present paper reviews the available research on Britanin in gastrointestinal tumors. It also outlines novel research directions using data not directly concerned with the digestive system, but which could be adopted in future gastrointestinal research. Britanin was found to counteract liver, colorectal, pancreatic, and gastric tumors, by regulating proliferation, apoptosis, autophagy, immune response, migration, and angiogenesis. As confirmed in pancreatic, gastric, and liver cancer, its most commonly noted molecular effects include nuclear factor kappa B and B-cell lymphoma 2 downregulation, as well as Bcl-2-associated X protein upregulation. Moreover, it has been found to induce the Akt kinase and Forkhead box O1 axis, activate the AMP-activated protein kinase pathway, elevate interleukin-2 and peroxisome proliferator-activated receptor-γ levels, reduce interleukin-10, as well as downregulate matrix metalloproteinase-9, Twist family bHLH transcription factor 1, and cyclooxygenase-2. It also inhibits Myc-HIF1α interaction and programmed death ligand 1 transcription by interrupting the Ras/ RAF/MEK/ERK pathway and mTOR/P70S6K/4EBP1 signaling. Future research should aim to unravel the link between Britanin and acetylcholinesterase, mast cells, osteolysis, and ischemia, as compelling data have been provided by studies outside the gastrointestinal context. Since the cytotoxicity of Britanin on noncancerous cells is significantly lower than that on tumor cells, while still being effective against the latter, further in-depth studies with the use of animal models are merited. The compound exhibits pleiotropic biological activity and offers considerable promise as an anti-cancer agent, which may address the current paucity of treatment options and high mortality rate among patients with gastrointestinal tumors.

Acetylcholinesterase enzyme among cancer patients a potential diagnostic and prognostic indicator a multicenter case-control study

Acetylcholinesterase enzyme (AChE) activity is impaired by a variety of inhibitors including organophosphorus pesticides, leading to the accumulation of acetylcholine. In this study, we aimed to determine the association between cancer and the blood level of the (AChE). This is a multicenter hospital-based case-control study conducted in the Radiation and Isotopes Center Khartoum, and Institute of Nuclear Medicine and Molecular Biology and Oncology Gezira. One hundred and fifty participants, half of them cancer patients and half cancer free were recruited. All participants were screened for demographic, environmental, occupational, and clinical characteristics. Blood for the (AChE) activity test was drawn from participants in the two groups. The mean age of the participants was 40.6 ± 14.8 years. Geographical distribution showed the Central Region of Sudan had the highest rate of cancer, followed by North State, Khartoum State, West State, and East State. The most common tumor subtype was breast cancer, followed by leukemia, colon, esophageal, and prostate cancer. Inferential analysis revealed significantly impaired (AChE) activity among cancer patients compared to controls (53.4 ± 20.3% vs. 93.8 ± 8.8, p-value 0.001). There was a significant statistical association between impaired (AChE) activity and cancer. (AChE) activity might be applied in the future as a diagnostic biomarker and therapeutic target. Further large sample and molecular studies are recommended.